This invention relates to a horn flare and more particularly, though not exclusively, to a horn flare used in conjunction with a solenoid-operated diaphragm horn for a motor vehicle.
Horn flares are known which are composed of two interengaging parts which together define between them a sinuous air passage. In one such horn flare, (as disclosed in British Patent Specification No. 1432363 corresponding to Japanese Provisional Publication No. 49-51895), two mouldings each have concentrically arranged spaced annular walls which extend integrally from an end wall. The two mouldings are interengaged so that the annular walls in each moulding engage in spaces in the other moulding with the free ends of the annular walls of each moulding being spaced from the end wall of the other moulding, so that a sinuous passage having runs extending axially of the horn flare is defined between the mouldings. In order to fix the mouldings in the required mutual disposition both radially and axially, such horn flare is provided with three equi-angularly spaced spacer lugs which extend radially and integrally from one of the annular walls of one moulding to engage against one of the annular walls of the other moulding. It is to be appreciated that the two last mentioned annular walls are not mutually parallel, (i) because of the dimensional changes required along the length of the air passage for horn performance purposes, and (ii) for ease of mould tool separation during formation of the mouldings. Thus, during assembly of the horn flare, the two mouldings are interengaged until the spacer lugs on one of the mouldings engages against the respective annular wall of the other moulding and then ultrasonically welded three radially movable probes to effect welding in the region of the lugs. However, if the two mouldings are engaged with excessive force, it will be appreciated that the walls can be deformed with the result that the required spacing is not obtained between the two mouldings, so that the shape of the air passage is altered and the performance of the horn flare suffers. Furthermore, problems are created in the welding together of the two mouldings because precise positioning and synchronisation of the ultrasonic welding probes are required to obtain the required spacing between the mouldings.
It is an object of the present invention to obviate or mitigate this disadvantage.
According to the present invention, there is provided a horn flare comprising first and second mutually interengaged mouldings and means interconnecting the two mouldings, said first moulding having a first end wall and a first annular wall extending integrally from one end face of the first end wall, the first end wall having an opening therethrough which communicates with the space internally of the first annular wall, the second moulding having a second end wall, a second annular wall extending integrally from the second end wall so that the latter closes one end of the second annular wall, a further wall surrounding the second annular wall, said interconnecting means holding the mouldings in the desired mutual disposition so that the free end of the annular wall of each moulding is spaced from the respective end wall of the other moulding whereby a sinuous air passage is defined by the interengaged mouldings, characterised in that the further wall is in the form of an open-ended sleeve, spacer means integrally interconnect the sleeve with the second annular wall, and the interconnecting means comprises an interengaging lug and recess arrangement between the sleeve and the first end wall.
The provision of the interengaging lug and recess arrangement between one end of the sleeve and the first end wall ensures that a positive engagement can be made between the two mouldings consistently.
Preferably, the interengaging lug and recess arrangement comprises an annular collar extending from said one face of the first end wall and having an annular recess in its free end, and an annular lug extending from said one end of the sleeve.
It is within the scope of the present invention to provide each moulding with one or more additional annular walls, the additional wall or walls on the first moulding being spaced outwardly of the first annular wall and the additional wall or walls on the second moulding being spaced inwardly of the second annular wall, whereby the length of the air passage is increased.
An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: